Alcohol-based low-cost dry powder coating special for casting and preparation method thereof
By using solid waste red mud and specific materials to construct a three-dimensional network structure bonding system, the problem of high cost of alcohol-based casting dry powder coatings was solved, and low-cost and high-performance coating preparation was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QUFU XIANFENG CASTING MATERIAL CO LTD
- Filing Date
- 2026-03-17
- Publication Date
- 2026-06-09
Smart Images
Figure CN122164855A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of coating technology, specifically to a low-cost dry powder coating for alcohol-based casting and its preparation method. Background Technology
[0002] Alcohol-based casting-specific dry powder coating is a low-cost powder material used for surface treatment of castings. It is mainly composed of refractory aggregates, combined with binders and other additives, and is made into dry powder through drying, crushing and mixing. When using it, simply add an alcohol solvent (such as ethanol) and stir to form a slurry for coating. This coating has the characteristics of good suspension, smooth brushing, fast drying, strong high-temperature crack resistance, smooth casting surface, and easy peeling.
[0003] Existing alcohol-based casting dry powder coatings rely on high-cost organic resins or silica sols as film-forming substrates for their binder systems. These raw materials are expensive due to fluctuations in petrochemical raw material prices. Furthermore, to meet higher performance requirements, high-specification resins or silica sols are often required, leading to a sharp increase in the cost of dry powder coatings as performance improves, thus exacerbating cost pressures. Therefore, this invention provides a low-cost dry powder coating specifically for alcohol-based casting and its preparation method. Summary of the Invention
[0004] The purpose of this invention is to provide a low-cost dry powder coating for alcohol-based casting and its preparation method, so as to solve the problems mentioned in the background art.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a low-cost dry powder coating for alcohol-based casting, comprising the following raw materials by weight: 40-60 parts mica powder, 20-40 parts attapulgite, 10-20 parts kaolin, 2-4 parts polyvinyl butyral, 4-6 parts powder, 6-10 parts additives, and 4-6 parts bauxite. The additive is prepared by the following method: S1: Preparation of binder. The raw materials of binder include red mud, oxalic acid solution, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile, and mixture. The raw materials of mixture include β-hemihydrate gypsum, magnesium olivine, lithium-based bentonite, and nano-silica aerogel. S2: Preparation of auxiliary materials. The raw materials for the auxiliary materials include magnesium oxide powder and graphene oxide aqueous solution. The mass of the auxiliary materials is 20-30% of the mass of the binder. S3: Mixing process, the binder and auxiliary materials are mixed to obtain the additive.
[0006] Preferably, the powder preparation method is as follows: hexagonal boron nitride and N-methylpyrrolidone are added to a reaction vessel, the reaction vessel is set at a temperature of 60-80℃ and a rotation speed of 200-400rpm, and the mixture is stirred at a constant temperature for 40-60min. The resulting product is subjected to ultrasonic exfoliation treatment with a power of 800-1200W for 2-4h. The resulting product is centrifuged to obtain a precipitate, and then dried to obtain the powder.
[0007] Preferably, the mass ratio of hexagonal boron nitride to N-methylpyrrolidone is 1:(10-20).
[0008] Preferably, the preparation method of the binder is as follows: red mud and oxalic acid solution are mixed in a mixer and then added to a planetary ball mill. The mixture is milled at 300-400 rpm and 40-60℃ for 1-2 hours. The resulting product is washed with deionized water until neutral and then dried in an oven to obtain coarse material. The coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile, and the mixture are added to a reaction vessel and stirred at 70-80℃ and 100-200 rpm for 3-5 hours. The resulting product is centrifuged to obtain precipitate, which is then dried to obtain the binder. The ball-to-material ratio in the planetary ball mill is 10:1.
[0009] Preferably, the mass ratio of red mud to oxalic acid solution is 1:(0.4-0.6), the mass concentration of oxalic acid solution is 5%, and the mass ratio of coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, and mixture is 1:(1.4-1.8):(0.6-0.8):(0.04-0.06):(0.8-1), with the mass of azobisisobutyronitrile being 2-4% of the mass of N-isopropylacrylamide.
[0010] Preferably, the preparation method of the mixture is as follows: β-hemihydrate gypsum, magnesium olivine and lithium-based bentonite are added to a mixer and mixed, and then nano-silica aerogel is added to the mixer and mixed at 800-1200 rpm for 20-40 min. The resulting product is then matured at 50-70℃ for 1-2 h to obtain the mixture.
[0011] Preferably, the mass ratio of β-hemihydrate gypsum, forsterite, and lithium-based bentonite is 1:(0.2-0.4):(0.6-0.8), and the mass of nano-silica aerogel is 6-10% of the mass of β-hemihydrate gypsum.
[0012] Preferably, the preparation method of the auxiliary material is as follows: magnesium oxide powder is dispersed in an aqueous solution of graphene oxide, and after spray drying, the resulting product is transferred into a muffle furnace and treated at 400-500℃ for 1-2 hours under an argon atmosphere to obtain the auxiliary material. The spray drying is set with an inlet temperature of 180-220℃ and an outlet temperature of 80-100℃.
[0013] Preferably, the particle size of magnesium oxide powder is 2-10 μm, the concentration of graphene oxide aqueous solution is 1-2 mg / mL, and the mass ratio of magnesium oxide powder to graphene oxide aqueous solution is 1:(4-6).
[0014] Preferably, a method for preparing a low-cost dry powder coating for alcohol-based casting includes the following steps: weighing out mica powder, attapulgite, kaolin, powder, and bauxite as needed and adding them to a mixing tank; setting the temperature to 80-100℃ and the speed to 80-100rpm and processing for 30-40 minutes; then adding polyvinyl butyral and additives and continuing to stir for 50-70 minutes to obtain the low-cost dry powder coating for alcohol-based casting.
[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In this invention, solid waste red mud is used as the core substrate of the binder. The inert oxide layer on its surface is removed by activating it with oxalic acid solution, exposing a highly active porous skeleton of aluminosilicate. Then, through ball milling and lignin sulfonate / thermosensitive monomer composite modification, a low-cost bonding system with a three-dimensional network structure is constructed. Furthermore, the calcium and magnesium ions of β-hemihydrate gypsum and forsterite in the mixture neutralize the surface charge of the red mud skeleton through charge balancing, reducing electrostatic repulsion and enhancing bonding durability. This not only ensures the comprehensive performance of the dry powder coating, but also significantly reduces the raw material cost by replacing traditional high-priced silica sol and resin raw materials with solid waste.
[0016] 2. In this invention, with the synergistic effect of the various raw material components, the boron nitride is exfoliated and formed into sheets by ultrasonic dissociation, which are inserted into the intergranular gaps of lithium-based bentonite, blocking the capillary penetration path of high-temperature molten metal. The magnesium oxide coated with graphene oxide, with its gradient thermal conductivity network, improves the thermal conductivity of the coating while accelerating the diffusion of alcohol solvent and inhibiting drying stress cracks. In the process, it works synergistically with the thermosensitive phase change behavior of N-isopropylacrylamide to make the particles denser and bonded and solidified. With the support of bauxite and mica powder, the suspension stability and dry strength of the dry powder coating are ensured, and the high-temperature anti-peeling property and storage stability of the coating are significantly improved. Attached Figure Description
[0017] Figure 1 The flowchart presents a low-cost dry powder coating for alcohol-based casting and its preparation method. Detailed Implementation
[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Example
[0020] A low-cost dry powder coating for alcohol-based casting comprises the following raw materials in parts by weight: 40 parts mica powder, 20 parts attapulgite, 10 parts kaolin, 2 parts polyvinyl butyral, 4 parts powder, 6 parts additives, and 4 parts bauxite. The additive is prepared by the following method: S1: Preparation of binder. The raw materials of binder include red mud, oxalic acid solution, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile, and mixture. The raw materials of mixture include β-hemihydrate gypsum, magnesium olivine, lithium-based bentonite, and nano-silica aerogel. S2: Preparation of auxiliary materials. The raw materials for the auxiliary materials include magnesium oxide powder and graphene oxide aqueous solution. The mass of the auxiliary materials is 20% of the mass of the binder. S3: Mixing process, the binder and auxiliary materials are mixed to obtain the additive.
[0021] The powder preparation method is as follows: hexagonal boron nitride and N-methylpyrrolidone are added to a reaction vessel. The reaction vessel is set to a temperature of 60℃ and a rotation speed of 200 rpm. The mixture is stirred at a constant temperature for 40 min. The resulting product is subjected to ultrasonic exfoliation treatment with a power of 800W for 2 h. The resulting product is centrifuged to obtain a precipitate and then dried to obtain the powder.
[0022] The mass ratio of hexagonal boron nitride to N-methylpyrrolidone is 1:10.
[0023] The preparation method of the binder is as follows: red mud and oxalic acid solution are mixed in a mixer and then added to a planetary ball mill. The mill is set at 300 rpm and 40 ℃ for 1 hour. The product is washed with deionized water until neutral and then dried in an oven to obtain coarse material. The coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile and the mixture are added to a reaction vessel and stirred at 70 ℃ and 100 rpm for 3 hours. The product is centrifuged to obtain precipitate, and then dried to obtain the binder. The ball-to-material ratio in the planetary ball mill is 10:1.
[0024] The mass ratio of red mud to oxalic acid solution is 1:0.4, the mass concentration of oxalic acid solution is 5%, the mass ratio of coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide and mixture is 1:1.4:0.6:0.04:0.8, and the mass of azobisisobutyronitrile is 2% of the mass of N-isopropylacrylamide.
[0025] The preparation method of the mixture is as follows: β-hemihydrate gypsum, magnesium olivine and lithium-based bentonite are added to a mixer and mixed. Then, nano-silica aerogel is added to the mixer and mixed at 800 rpm for 20 min. The resulting product is matured at 50℃ for 1 h to obtain the mixture.
[0026] The mass ratio of β-hemihydrate gypsum, forsterite, and lithium-based bentonite is 1:0.2:0.6, and the mass of nano-silica aerogel is 6% of the mass of β-hemihydrate gypsum.
[0027] The preparation method of the auxiliary material is as follows: magnesium oxide powder is dispersed in an aqueous solution of graphene oxide, and after spray drying, the resulting product is transferred into a muffle furnace and treated at 400°C for 1 hour under an argon atmosphere to obtain the auxiliary material. The spray drying is set with an inlet temperature of 180°C and an outlet temperature of 80°C.
[0028] The magnesium oxide powder has a particle size of 2 μm, the graphene oxide aqueous solution has a concentration of 1 mg / mL, and the mass ratio of magnesium oxide powder to graphene oxide aqueous solution is 1:4.
[0029] One method for preparing a low-cost dry powder coating for alcohol-based casting includes the following steps: weigh out mica powder, attapulgite, kaolin, powder, and bauxite as needed and put them into a mixing tank. Set the temperature to 80℃ and 80rpm and process for 30 minutes. Then add polyvinyl butyral and additives and continue stirring for 50 minutes to obtain the low-cost dry powder coating for alcohol-based casting. Example
[0030] A low-cost dry powder coating for alcohol-based casting comprises the following raw materials in parts by weight: 50 parts mica powder, 30 parts attapulgite, 15 parts kaolin, 3 parts polyvinyl butyral, 5 parts powder, 8 parts additives, and 5 parts bauxite. The additive is prepared by the following method: S1: Preparation of binder. The raw materials of binder include red mud, oxalic acid solution, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile, and mixture. The raw materials of mixture include β-hemihydrate gypsum, magnesium olivine, lithium-based bentonite, and nano-silica aerogel. S2: Preparation of auxiliary materials. The raw materials for the auxiliary materials include magnesium oxide powder and graphene oxide aqueous solution. The mass of the auxiliary materials is 25% of the mass of the binder. S3: Mixing process, the binder and auxiliary materials are mixed to obtain the additive.
[0031] The powder preparation method is as follows: hexagonal boron nitride and N-methylpyrrolidone are added to a reaction vessel. The reaction vessel is set to a temperature of 70°C and a rotation speed of 300 rpm. The mixture is stirred at a constant temperature for 50 min. The resulting product is subjected to ultrasonic exfoliation treatment with a power of 1000 W for 3 h. The resulting product is centrifuged to obtain a precipitate and then dried to obtain the powder.
[0032] The mass ratio of hexagonal boron nitride to N-methylpyrrolidone is 1:15.
[0033] The preparation method of the binder is as follows: red mud and oxalic acid solution are mixed in a mixer and then added to a planetary ball mill. The mill is set at 350 rpm and 50 ℃ for 1.5 h. The product is washed with deionized water until neutral and then dried in an oven to obtain coarse material. The coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile and the mixture are added to a reaction vessel and stirred at 75 ℃ and 150 rpm for 4 h. The product is centrifuged to obtain precipitate, and then dried to obtain the binder. The ball-to-material ratio in the planetary ball mill is 10:1.
[0034] The mass ratio of red mud to oxalic acid solution is 1:0.5, the mass concentration of oxalic acid solution is 5%, the mass ratio of coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, and mixture is 1:1.6:0.7:0.05:0.9, and the mass of azobisisobutyronitrile is 3% of the mass of N-isopropylacrylamide.
[0035] The preparation method of the mixture is as follows: β-hemihydrate gypsum, magnesium olivine and lithium-based bentonite are added to a mixer and mixed. Then, nano-silica aerogel is added to the mixer and mixed at 1000 rpm for 30 min. The resulting product is matured at 60℃ for 1.5 h to obtain the mixture.
[0036] The mass ratio of β-hemihydrate gypsum, forsterite, and lithium-based bentonite is 1:0.3:0.7, and the mass of nano-silica aerogel is 8% of the mass of β-hemihydrate gypsum.
[0037] The preparation method of the auxiliary material is as follows: magnesium oxide powder is dispersed in an aqueous solution of graphene oxide, and after spray drying, the resulting product is transferred into a muffle furnace and treated at 450°C for 1.5 hours under an argon atmosphere to obtain the auxiliary material. The spray drying is set with an inlet temperature of 200°C and an outlet temperature of 90°C.
[0038] The magnesium oxide powder has a particle size of 7 μm, the graphene oxide aqueous solution has a concentration of 1.5 mg / mL, and the mass ratio of magnesium oxide powder to graphene oxide aqueous solution is 1:5.
[0039] One method for preparing a low-cost dry powder coating for alcohol-based casting includes the following steps: weigh out mica powder, attapulgite, kaolin, powder, and bauxite as needed and put them into a mixing tank. Set the temperature to 90℃ and 90rpm and process for 35 minutes. Then add polyvinyl butyral and additives and continue stirring for 60 minutes to obtain the low-cost dry powder coating for alcohol-based casting. Example
[0040] A low-cost dry powder coating for alcohol-based casting comprises the following raw materials in parts by weight: 60 parts mica powder, 40 parts attapulgite, 20 parts kaolin, 4 parts polyvinyl butyral, 6 parts powder, 10 parts additives, and 6 parts bauxite. The additive is prepared by the following method: S1: Preparation of binder. The raw materials of binder include red mud, oxalic acid solution, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile, and mixture. The raw materials of mixture include β-hemihydrate gypsum, magnesium olivine, lithium-based bentonite, and nano-silica aerogel. S2: Preparation of auxiliary materials. The raw materials for the auxiliary materials include magnesium oxide powder and graphene oxide aqueous solution. The mass of the auxiliary materials is 30% of the mass of the binder. S3: Mixing process, the binder and auxiliary materials are mixed to obtain the additive.
[0041] The powder preparation method is as follows: hexagonal boron nitride and N-methylpyrrolidone are added to a reaction vessel. The reaction vessel is set to a temperature of 80℃ and a rotation speed of 400 rpm. The mixture is stirred at a constant temperature for 60 min. The resulting product is subjected to ultrasonic exfoliation treatment with a power of 1200W for 4 h. The resulting product is centrifuged to obtain a precipitate and then dried to obtain the powder.
[0042] The mass ratio of hexagonal boron nitride to N-methylpyrrolidone is 1:20.
[0043] The preparation method of the binder is as follows: red mud and oxalic acid solution are mixed in a mixer and then added to a planetary ball mill. The mill is set at 400 rpm and 60 ℃ for 2 hours. The product is washed with deionized water until neutral and then dried in an oven to obtain coarse material. The coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile and the mixture are added to a reaction vessel and stirred at 80 ℃ and 200 rpm for 5 hours. The product is centrifuged to obtain precipitate, and then dried to obtain the binder. The ball-to-material ratio in the planetary ball mill is 10:1.
[0044] The mass ratio of red mud to oxalic acid solution is 1:0.6, the mass concentration of oxalic acid solution is 5%, the mass ratio of coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, and mixture is 1:1.8:0.8:0.06:1, and the mass of azobisisobutyronitrile is 4% of the mass of N-isopropylacrylamide.
[0045] The preparation method of the mixture is as follows: β-hemihydrate gypsum, magnesium olivine and lithium-based bentonite are added to a mixer and mixed. Then, nano-silica aerogel is added to the mixer and mixed at 1200 rpm for 40 min. The resulting product is matured at 70℃ for 2 h to obtain the mixture.
[0046] The mass ratio of β-hemihydrate gypsum, forsterite, and lithium-based bentonite is 1:0.4:0.8, and the mass of nano-silica aerogel is 10% of the mass of β-hemihydrate gypsum.
[0047] The preparation method of the auxiliary material is as follows: magnesium oxide powder is dispersed in an aqueous solution of graphene oxide, and after spray drying, the resulting product is transferred into a muffle furnace and treated at 500°C for 2 hours under an argon atmosphere to obtain the auxiliary material. The spray drying is set with an inlet temperature of 220°C and an outlet temperature of 100°C.
[0048] The magnesium oxide powder has a particle size of 10 μm, the graphene oxide aqueous solution has a concentration of 2 mg / mL, and the mass ratio of magnesium oxide powder to graphene oxide aqueous solution is 1:6.
[0049] One method for preparing a low-cost dry powder coating for alcohol-based casting includes the following steps: weigh out mica powder, attapulgite, kaolin, powder, and bauxite as needed and put them into a mixing tank. Set the temperature to 100℃ and 100rpm and process for 40 minutes. Then add polyvinyl butyral and additives and continue stirring for 70 minutes to obtain the low-cost dry powder coating for alcohol-based casting.
[0050] Comparative Example 1: The difference between this comparative example and Example 1 is that no excipients are added during the preparation of the additive in this comparative example.
[0051] Comparative Example 2 differs from Example 1 in that no binder is added during the preparation of the additive in this comparative example.
[0052] Comparative Example 3: The difference between this comparative example and Example 1 is that this comparative example does not contain any additives.
[0053] Comparative Example 4 differs from Example 1 in that ordinary hexagonal boron nitride is used to replace the powder in this comparative example.
[0054] The suspension stability and dry strength of the dry powder coatings prepared in Examples 1-3 and Comparative Examples 1-4 were tested in accordance with the JB / T9226-2008 standard.
[0055] Performance testing: The performance of the low-cost dry powder coatings for casting prepared in Examples 1-3 and Comparative Examples 1-4 was tested, and the test data are recorded in the table below.
[0056] Table 1:
[0057] Comparative analysis of the data in the table shows that the suspension stability and dry strength of the low-cost dry powder coatings for alcohol-based casting prepared in Examples 1-3 are better than those prepared in Comparative Examples 1-4. This demonstrates that by using solid waste red mud as the core substrate of the binder, its surface inert oxide layer is peeled off through oxalic acid solution to expose a highly active porous skeleton of aluminosilicate. Then, through ball milling and lignin sulfonate / thermosensitive monomer composite modification, a low-cost bonding system with a three-dimensional network structure is constructed. Furthermore, the calcium and magnesium ions of β-hemihydrate gypsum and forsterite in the mixture neutralize the surface charge of the red mud skeleton through charge balancing, reducing electrostatic repulsion and enhancing bonding durability. This not only ensures the comprehensive performance of the dry powder coating, but also significantly reduces raw material costs by replacing traditional high-priced silica sol and resin with solid waste. Combined with the natural mineral composite skeleton of attapulgite and kaolin, the overall cost is effectively reduced while ensuring the basic performance of the coating, breaking through the cost bottleneck caused by the reliance on high-priced refractory aggregates in alcohol-based coatings. Meanwhile, with the synergy of the various raw material components, the boron nitride is exfoliated and formed into sheets through ultrasonic dissociation, which are inserted into the intergranular gaps of lithium-based bentonite, blocking the capillary penetration path of high-temperature molten metal. The magnesium oxide coated with graphene oxide, with its gradient thermal conductivity network, improves the thermal conductivity of the coating while accelerating the diffusion of alcohol solvent and inhibiting drying stress cracks. In the process, it works synergistically with the thermosensitive phase change behavior of N-isopropylacrylamide to densify and solidify the particles. With the support of bauxite and mica powder, it ensures the suspension stability and dry strength of the dry powder coating, and significantly improves the high-temperature anti-peeling properties and storage stability of the coating.
[0058] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0059] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A low-cost dry powder coating for alcohol-based casting, characterized in that, The raw materials include the following parts by weight: 40-60 parts mica powder, 20-40 parts attapulgite, 10-20 parts kaolin, 2-4 parts polyvinyl butyral, 4-6 parts powder, 6-10 parts additives, and 4-6 parts bauxite. The additive is prepared by the following method: S1: Preparation of binder. The raw materials of binder include red mud, oxalic acid solution, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, azobisisobutyronitrile, and mixture. The raw materials of mixture include β-hemihydrate gypsum, magnesium olivine, lithium-based bentonite, and nano-silica aerogel. S2: Preparation of auxiliary materials. The raw materials for the auxiliary materials include magnesium oxide powder and graphene oxide aqueous solution. The mass of the auxiliary materials is 20-30% of the mass of the binder. S3: Mixing process, the binder and auxiliary materials are mixed to obtain the additive.
2. The low-cost dry powder coating for alcohol-based casting according to claim 1, characterized in that, The preparation method of the powder is as follows: hexagonal boron nitride and N-methylpyrrolidone are added to a reaction vessel. The reaction vessel is set at a temperature of 60-80℃ and a rotation speed of 200-400 rpm. The mixture is stirred at a constant temperature for 40-60 minutes. The resulting product is subjected to ultrasonic exfoliation treatment with a power of 800-1200W for 2-4 hours. The resulting product is centrifuged to obtain a precipitate, and then dried to obtain the powder.
3. The low-cost dry powder coating for alcohol-based casting according to claim 2, characterized in that, The mass ratio of hexagonal boron nitride to N-methylpyrrolidone is 1:(10-20).
4. The low-cost dry powder coating for alcohol-based casting according to claim 1, characterized in that, The binder is prepared as follows: red mud and oxalic acid solution are mixed in a mixer and then added to a planetary ball mill. The mill is set at 300-400 rpm and 40-60℃ for 1-2 hours. The product is washed with deionized water until neutral and then dried in an oven to obtain coarse material. The coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, and azobisisobutyronitrile are added to a reaction vessel and stirred at 70-80℃ and 100-200 rpm for 3-5 hours. The product is centrifuged to obtain precipitate, which is then dried to obtain the binder. The ball-to-material ratio in the planetary ball mill is 10:
1.
5. The low-cost dry powder coating for alcohol-based casting according to claim 4, characterized in that, The mass ratio of red mud to oxalic acid solution is 1:(0.4-0.6), the mass concentration of oxalic acid solution is 5%, and the mass ratio of coarse material, calcium lignosulfonate, sodium hydroxide solution, N-isopropylacrylamide, and mixture is 1:(1.4-1.8):(0.6-0.8):(0.04-0.06):(0.8-1). The mass of azobisisobutyronitrile is 2-4% of the mass of N-isopropylacrylamide.
6. The low-cost dry powder coating for alcohol-based casting according to claim 5, characterized in that, The preparation method of the mixture is as follows: β-hemihydrate gypsum, magnesium olivine and lithium-based bentonite are added to a mixer and mixed. Then, nano-silica aerogel is added to the mixer and mixed at 800-1200 rpm for 20-40 min. The resulting product is matured at 50-70℃ for 1-2 h to obtain the mixture.
7. The low-cost dry powder coating for alcohol-based casting according to claim 6, characterized in that, The mass ratio of β-hemihydrate gypsum, forsterite, and lithium-based bentonite is 1:(0.2-0.4):(0.6-0.8), and the mass of nano-silica aerogel is 6-10% of the mass of β-hemihydrate gypsum.
8. The low-cost dry powder coating for alcohol-based casting according to claim 1, characterized in that, The preparation method of the auxiliary material is as follows: magnesium oxide powder is dispersed in an aqueous solution of graphene oxide, and after spray drying, the resulting product is transferred into a muffle furnace and treated at 400-500℃ for 1-2 hours under an argon atmosphere to obtain the auxiliary material. The spray drying is set with an inlet temperature of 180-220℃ and an outlet temperature of 80-100℃.
9. The low-cost dry powder coating for alcohol-based casting according to claim 8, characterized in that, The particle size of magnesium oxide powder is 2-10 μm, the concentration of graphene oxide aqueous solution is 1-2 mg / mL, and the mass ratio of magnesium oxide powder to graphene oxide aqueous solution is 1:(4-6).
10. A method for preparing a low-cost dry powder coating for alcohol-based casting according to any one of claims 1 to 9, characterized in that, The process includes the following steps: Weigh out mica powder, attapulgite, kaolin, powder, and bauxite as needed and put them into a mixing tank. Set the temperature to 80-100℃ and the speed to 80-100rpm and process for 30-40 minutes. Then add polyvinyl butyral and additives and continue stirring for 50-70 minutes to obtain a low-cost dry powder coating for alcohol-based casting.